Models manufactured from 1996 onwards use the Manifold Absolute Pressure (MAP) sensor as an intake manifold pressure and ambient barometric changes detector. In addition, for models of 1996-1999 there is also a solenoid in combination with the MAP sensor while from 2000 up to date they are not used. For example, on the 2004 models of this vehicle, the MAP sensor is part of the PCM and cannot be replaced independently. The purpose of using this MAP sensor signal by the PCM is diagnostic. At close throttle this voltage output signal from MAP sensor reads about 0.5 volts, whereas it can reach up to approximately as wide open throttle about 5.0 volts respectively. Furthermore, these are located at the back of left-bank cylinder head-MAP SENSOR AND SOLENOID VALVE.The next step is to attach a vacuum gauge after disconnecting the vacuum hose to check your MAP sensor. Once it does, go ahead with the checking of your MAP sensors.To test for voltage from PCM disconnect electrical connector and check specified voltage.Remove solenoid valve and check for battery voltage by disconnecting electrical connector.It's easy to test if you have removed it from vehicle only that you will have removed it too.You can replace both battery cable and electrical connector but not vacuum hose(s) when replacing MAP sensor or/and a solenoid valve.Sensor or valve as well as mounting screws should be separated.Charles was told to replace what he had removed surrounding it.